KR101736722B1 - Printing semiconductor elements by shear-assisted elastomeric stamp transfer - Google Patents

Abstract

A method and apparatus for transfer printing of semiconductor devices on a receiving substrate are provided. In one aspect, the printing is in conformal contact between the elastomeric stamp painted with the ink in the semiconductor element and the receiving substrate, and during stamp removal, a shear offset is applied between the stamp and the receiving substrate. The shear-offset printing process achieves high printing transfer gain with good batch precision. Processing parameter selection during transfer printing, including stamp-backing pressure application and time varying vertical displacement, results in a sufficiently constant delamination rate with subsequent transfer printing improvements.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a printing semiconductor device by a shear-assistant elastic stamp transfer,

This application claims the benefit of U.S. Provisional Application No. 61 / 116,136, filed November 19, 2008, which is expressly incorporated by reference to the extent not inconsistent.

The present invention is made, at least in part, by US government support awarded by the US National Science Foundation Grant IIP-0712017. In this invention, the US government has certain rights.

Semiconductor chip or die automated assembly equipment typically includes a placement head operated in a vacuum, often referred to as a vacuum gripper or a pick-and-place mechanism, Lt; / RTI > In a simple embodiment, these placement heads generally consist of an open ended cylinder having a drilled nozzle face sealing the die to achieve a physical bond. Ultra thin, fragile or very small semiconductor chips or dies can not be economically processed by conventional vacuum grippers. As a result, alternatives such as self-assembly or dry transfer printing techniques have been studied.

Transcription printing enables massively parallel assembly to virtually any substrate material, including glass, plastic, metal or other semiconductors (see, for example, US Pat. App. App. No. 11 / 145,574 METHODS AND DEVICES FOR FABRICATING AND ASSEMBLING PRINTABLE SEMICONDUCTOR ELEMENTS). This semiconductor transfer printing technique relies on the use of a microstructured elastomeric stamp to selectively pick up the device from the source wafer and then prints these devices on the target substrate.

While the pick and place mechanism depends on the suction force, the dry transfer printing mechanism relies on the surface adhesion force to control the pickup and release of the semiconductor device. In order to facilitate dry transfer printing, a method for controlling the adhesive force between the semiconductor element and the elastic stamp is required. One such method is US Pat. App. No. 11 / 423,192 "PATTERN TRANSFER PRINTING BY KINETIC CONTROL OF ADHESION TO AN ELASTOMERIC STAMP &quot;. In this method, the elastic stamp adhesion force is controlled by adjusting the peeling ratio of the elastic transfer stamp. Control of the separation or peeling ratio provides a means for increasing the stamp adhesion force required to pick up a semiconductor element from the source wafer. However, there is a problem associated with transferring the semiconductor device from the stamp to the receiving substrate for this technique. First, a slow stamp peel ratio (< 1 mm / s) is often required to transfer semiconductor devices onto a substrate coated with a bare target substrate or a low tack adhesive. This increases processing time and adversely affects the ability to perform high throughput of transcription printing. Second, stamps optimized for dry transfer printing semiconductor devices with high placement accuracy typically use a rigid backing layer. During the printing or transfer step, when the stiff backing layer undergoes a bending force, the peel rate of these stamps can be unstable and difficult to control. Third, the printing gain may be very low in the case of an extremely smooth or non-sticky side.

Thus, there is a need for an improved method for transferring a semiconductor device to print with high gain and placement accuracy, and a method, system, and process for expanding to a large size resilient stamp.

A method and system for dry transfer printing of semiconductor and semiconductor devices by shear offset is provided. The shear offset printing system allows a high separation rate to be achieved during transcription printing without loss of printing gain or precision, as compared to the prior art without shear offset applied. Thus, the methods and systems proposed herein provide faster and more reliable transfer printing, thereby reducing processing time and increasing printing efficiency.

Increasing the shear offset during the peeling process increases the transfer gain. The shear offset causes a mechanical deformation in the transfer stamp used to transfer the semiconductor device, thereby lowering the energy required to cause the transfer stamp surface to peel off from the semiconductor device. Another important parameter for good transcriptional benefit (eg, greater than 95% transcription) is a constant rate of exfoliation. What is provided here is a technique for optimizing a plurality of parameters to secure a constant separation rate with a minimum deviation. For example, the stamp may be a deformable layer, a geometric shape and pattern of relief features on the transverse surfaces of the deformable layer, Young's modulus, a relative thickness of the rigid backing layer connected to the deformable layer And is designed to provide an appropriate release rate by optimizing one or more combinations. Other parameters affecting the peel rate include, but are not limited to, the force (e.g., pressure) used to establish conformal contact as well as the rate at which the stamp is removed from the receiving substrate. In one aspect, each of these parameters varies over the course of the peel cycle to minimize deviation of the peel rate over the course of the printing step.

In one aspect, the present invention is a method of printing a transferable semiconductor element by providing an elastic stamp having, for example, a transfer surface. The semiconductor element is supported by the transfer surface. In order to further increase the control and printing gain, the transfer surface supporting the semiconductor element may have a three-dimensional pattern of relief features at least partially contacting the semiconductor element. When the "inked" stamp on the semiconductor element makes conformity with the receiving surface, at least a portion of the semiconductor element contacts the receiving surface. The receiving surface is optionally coated at least in part with an adhesive layer. Instead, the receiving surface is not covered with adhesive. Instead, the receiving surface is patterned with a pattern of adhesive resin. The elastic stamp offsets the horizontal distance with respect to the receiving surface, thereby creating a mechanical deformation in at least a portion of the pattern of the relief feature, wherein the offset does not separate the semiconductor element from the transfer surface or the receiving surface. If there is an offset between the receiving surface and the transfer surface, the area driving the offset is not critical (e.g., one or both of the stamp and the receiving surface may be offset). A "horizontal offset" relates to an offset that substantially aligns with a plane or surface defined by the contact between the inked contact surface and the receiving surface. The stamp is separated from the receiving surface, thereby printing the semiconductor element on the receiving surface.

In one aspect, the conformal contacting step is established, at least in part, by applying an air force to the top surface of the resilient stamp. For example, the stamp may be very close to the receiving surface (e.g., about 100 microns or less) and air force is applied to establish conformal contact. In an embodiment, the stamp is a composite stamp having a ridge backing layer, and the upper surface of the stamp corresponds to an upper surface (e.g., a surface facing the exposed surface or the transfer surface). The "top" side is understood to be a relative term used to distinguish the sides, depending on the geometrical configuration of the system, and in fact the upper side may be located in a downward position.

If the final result is a shift of the transfer surface relative to the receiving surface, offsetting may have any conventionally known meaning. In one embodiment, the offset is by application of in plane displacement to the elastic stamp. In one embodiment, the in-plane displacement can be obtained by horizontal displacement of the stamp top surface relative to the receiving surface of 5 占 퐉 or more and 100 占 퐉 or less.

In one aspect, the separating step includes a step of reducing the aerodynamic force applied to the upper surface of the stamp. Alternatively, the separating step comprises physically moving the stamp in a vertical direction from the receiving surface. In one aspect, the separating step includes both a step of reducing the air force and a movement in the vertical direction, either simultaneously or in a sequential manner.

In one embodiment, any stamp used in any process or apparatus shown herein may be a composite stamp. In one aspect, the elastic stamp includes an elastic layer with an upper surface facing the ridgebacking layer having a transfer surface and a bottom surface, and the bottom surface is positioned adjacent the upper surface of the elastic layer. This elastic stamp having a ridge backing layer is advantageous for transferring pressure and movement (e.g., vertical and / or horizontal) applied to the interface between the transfer surface and the semiconductor element painted with the ink and / or the receiving substrate surface. For example, the air force applied to the rigid backing can be uniformly transmitted to the active printing area. In another aspect, the elastic stamp also has a reinforcement layer operatively connected to the ridge backing layer, wherein the reinforcement layer has an opening in the transfer surface perpendicular to at least a portion of the relief feature.

In one aspect, any method provided herein further comprises the step of mounting an elastic stamp on a dry transfer printing mechanism. The offset step is performed selectively by applying an in-plane displacement to the dry transfer printing mechanism, thereby creating a mechanical displacement in at least a portion of the relief feature. "In-plane displacement" relates to the offset, which is a substantially parallel direction to the interface causing the exfoliation. In this respect, "substantially parallel" relates to a direction defined by the interface or within 2 [deg.] Of the plane.

In one embodiment of the invention, the conformal contact is established at least in part by applying pressure to the top surface of the mounted stamp, such as a top surface that is a ridge backing layer.

In the sense that the stamp is separated from the receiving surface by moving one of the surfaces in the vertical direction, such as by moving a transfer printing mechanism mounted on an elastic stamp in a direction perpendicular to the receiving surface, some or more of the parameters are changed during the peeling cycle . For example, the pressure applied to the stamp may be varied during vertical movement to separate the stamp from the receiving surface. In one embodiment, the pressure can be reduced from a maximum value to a minimum value, such as a maximum value between 4 kPa and 10 kPa and a minimum value between 0 kPa and 2 kPa. In one aspect, the pressure is selected such that the pressure drop ratio and the vertical travel rate are substantially proportional to the stripping rate of the stamp post from a constant receiving substrate (or from a semiconductor element supported by the receiving surface).

In one embodiment, the relief feature comprises a plurality of posts. The post may help lift the semiconductor device from the donor surface and / or enable transfer of the semiconductor device from the stamp to the receiving surface. In one aspect of this embodiment, the plurality of posts have a contacting area fraction on a transfer surface selected from the range of greater than or equal to 1% and less than or equal to 25%. The "contacting area fraction" relates to the percentage of the area coverage by the post over the printable area. In terms that the relief feature forms a plurality of groups, the relief feature includes a plurality of stabilization features interspersed between the posts and the fixation feature has a contact area that is smaller than the contact area of the post.

In one aspect, any of the methods provided herein are described with respect to functional parameters including, but not limited to, transcriptional printing gain. For example, the treatment can provide a gain of more than 99.5% over the receiving surface coated with a thin layer of adhesive. Alternatively, the gain may be at least 99.5% for a stamp peel ratio of 1 mm / s / or greater.

In certain embodiments, some methods include applying a pressure to the top surface of the stamp to optically align the stamp with the receiving surface, locate the semiconductor element at a vertical separation distance within 100 [mu] m from the receiving surface, and establish conformal contact between the stamp and the receiving surface . The pressure can be applied by means known in the art. For example, pressure can be applied by applying a constant air force to the top surface of the stamp, including the top surface corresponding to the ridge backing layer.

Any of the methods described herein can be used to print a single semiconductor element or a plurality of semiconductor elements, and the pattern of relief features supports a single or multiple semiconductor elements.

In one aspect, the transfer method provided herein is for transferring a semiconductor element to a receiving surface that is a low-tack surface.

The separation step is performed by any means known in the art including, but not limited to, stamping the receiving surface by applying a vertical offset to the stamp and / or receiving surface. This application may be direct or indirect, such as applying any offset to the structure supporting the face. Similarly, the step of offsetting is optionally provided by applying in-plane displacement to the stamp, applying in-plane displacement to the receiving surface, or applying in-plane displacement to both.

In terms of air force being applied to at least a portion in order to establish conformal contact and the stamp being vertically separated from the receiving surface, the air force and vertical separation ratio can vary over time during the stripping cycle. For example, in embodiments in which the peeling cycle is separated by at least two time intervals that are prior to the first time interval and do not substantially overlap, the airstream is maintained such that the vertical separation remains constant over the first time interval Lt; / RTI &gt; over a first time interval. On the other hand, while the vertical separation increases during the second time interval, the air force may remain constant during the second time interval. In this embodiment, the selection of the pressure and the draft distance in terms of time is an optimization step that easily facilitates a constant removal rate over the separation cycle, and this separation rate is less than or equal to 5% at the average separation rate over the first and second time intervals 0.0 &gt; user-specified &lt; / RTI &gt;

Another aspect of the present invention relates to an apparatus for dry transfer printing of semiconductors on a receiving substrate, which apparatus is capable of implementing any shear-offset process as described herein.

In one embodiment, the apparatus comprises a reinforced composite stamp having an inner surface and an outer surface positioned opposite the inner surface, and a deformable layer and an outer surface of the deformable layer having a plurality of relief features, . The rigid support layer is connected to the inner surface of the deformable layer, wherein the ramp support layer has an upper surface facing the bottom surface and the bottom surface, and the bottom surface is positioned proximate the deformable inner surface. A reinforcement layer is operatively connected to the rigid support layer and the enhancement layer has an opening perpendicular to at least a portion of the reel ripple feature of the outer surface of the deformable layer. In one embodiment, the composite stamp is supported by a vertical section operatively connecting a mounting flange to the deformable layer outer surface. A transfer printing mechanism head having a receiving surface connects the upper surface of the mounting flange. An actuator is operatively connected to a mounting flange or transfer printing mechanism head that generates a horizontal displacement between the deformable layer inner surface and the receiving surface. Thus, the actuator removes the stamp or receiving surface, thereby performing an offset between the stamp and the receiving surface.

If a controllable offset is performed, any actuator may be used. Examples of actuators include, but are not limited to, motors, stepper motors, micropositioners, pressure generators, or piezoelectric actuators. Other examples of offset generating actuators may not control the direct displacement and instead affect the physical parameters that cause the offset, such as the pressure generator, temperature controller, or voltage generator.

And arbitrarily includes a plurality of posts distributed to a plurality of relief outer surfaces. In one embodiment, a plurality of stationary features are distributed to the outer surface, and the height of the stationary feature is lower than the height of the posts. The fixed feature includes first and second populations, each population having a geometric footprint and the first population geometry footprint being greater than the second population geometry footprint. The "geometric footprint" relates to the effective surface area facing the receiving surface.

In one aspect, the apparatus is operatively connected to a rigid support layer of a composite stamp for controllably applying a positive pressure to an upper surface of the rigid support layer. The applied pressure is useful for establishing conformal contact between faces. In one embodiment, the pressure on the top surface is substantially uniform over the top surface of the rigid support layer. In one embodiment, the pressure may vary over time in the time of the peel cycle, although the pressure at a given time is substantially constant.

A review of the trust or understanding of the underlying principles or mechanisms in connection with an embodiment of the invention may be made without being bound by any particular theory. It will be appreciated that embodiments of the invention are effective and useful regardless of the ultimate accuracy of any explanation or hypothesis.

In accordance with the present invention, a shear offset printing system enables a high release rate to be achieved during transfer printing, without loss of printing gain or precision, as compared to the prior art where no shear offset is applied.

Thus, the proposed method and system of the present invention provides faster and more reliable transfer printing, thereby reducing processing time and increasing printing efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a process flow diagram as a cross-sectional view illustrating steps for implementing one embodiment of shear offset printing. FIG. 1A is an illustration of an array of transfer printing stamps, FIG. 1B is a lamination of transfer printing stamps by applying air force to stamp backing, FIG. 1C illustrates moving the instrument head in a given X and / or Y position to apply in- 1d shows that the instrument head is moved up in the Z direction and at the same time the air force applied on the stamp backing is reduced to shrink the stamp into a thin slice layer.
2A is a diagram showing an example of a three-dimensional schematic view of a composite stamp to be used for shear-offset printing.
Figure 2b is a schematic cross-sectional view of various stamp posts used with shear offset printing.
Figure 3 is an illustration of an example of a layout for a relief feature on the transfer surface of an elastic stamp including an anti-sag and a stabilization feature.
4A is a schematic cross-sectional view illustrating a reinforced composite stamp attached to a transfer printing mechanism head device. FIG. 4A is a view showing an embodiment for a front end offset to a printing apparatus head, FIG. 4B is a view showing an embodiment for front end offset to a receiving substrate, and FIG. 4C is a photograph showing an embodiment of a transfer printing mechanism .
Figure 5 is a pictorial representation of the silicon chip transfer printing gain as a function of the shear offset applied to the reinforced composite stamp with the flange shown in Figure 4a. The insert represents a high resolution optical image of a 3x2 sub-array of transfer printed silicon chips.
6A is a schematic diagram illustrating a composite stamp model used to perform a finite element simulation of a stamp post with delamination from a substrate in a force applied state.
6B is a view showing a result of a finite element simulation of a stamp post to be peeled off from the substrate shown in FIG. 5A. The vertical displacement of the mesh element inside the stamp is represented using a contour plot.
7A is a plot of in silico as a result of the energy normalized to the calculated maximum energy required to peel the composite stamp post as a function of the shear offset applied to the stamped backing layer.
FIG. 7B is a plot of silylcoat as a result of the release rate of the composite stamp post as a function of the shear offset applied to the stamped backing layer.
8A is a schematic diagram of a composite stamp model used to perform a finite element simulation of a flat (unconfigured printing surface) stamp peeling off a substrate.
Fig. 8B is a view showing a finite element simulation as a result of the composite stamp of Fig. 7A to be peeled off the substrate. Fig. The vertical displacement of the mesh element inside the stamp is displayed. In order to improve drawing clarity, the shape-modified stamp is enlarged to a factor of 100.
9A is a view showing a finite element simulation as a result of a composite stamp with an edge length being a function of the aerodynamic force applied to the composite stamped glass backing.
9B is a view showing a finite element simulation as a result of an edge-length peeled composite stamp as a function of the vertical displacement at the stamp outer edge.
Figure 10A is a diagram that provides model predictions of the pressure profile over time to perform a constant release rate of 65 mm per normalized time unit of composite stamp.
10B is a view that provides model predictions of a vertical operating time course (e.g., a ratio of vertical separation between the stamp edge and the substrate) to perform a constant removal rate of the composite stamp.
Fig. 10C is a view that provides a finite element simulation as a result of composite stamp peel ratio by plotting the stripped edge length as a function of time (normalized) when an optimized pressure and vertical motion profile is implemented.

"Printing" relates to the process of transferring features, such as semiconductor elements, from a first side to a second side. In one aspect, the first surface is a donor surface, the second surface is a receiving surface, and the transfer is interposed by an intermediate surface, such as a stamp having a transfer surface. In one aspect, the first surface is a transfer surface on a stamp on which one or more semiconductor elements are supported, and the stamp emits the element to a receiving surface on the target substrate, thereby transferring the semiconductor element. In one aspect, the printing is dry transfer printing of a printable semiconductor, and the adhesion between the solid object and the stamp surface is rate-sensitive.

"Stamp" relates to the configuration for transfer, assembly and / or integration of structures and materials via printing, for example, dry transfer printing. The composite stamp is particularly useful for a pick-up and release / printing system, as described in 12 / 177,963, filed August 29, 2008, incorporated herein by reference, wherein the stamp is transferred from its donor substrate to a micro or nano And then contacted with a donor substrate for picking up the structure and then contacted with a receiving substrate to which the micro-or nano structure is transferred, which can be firstly laminated or contacted.

A "composite stamp" relates to a stamp having one or more components, such as one or more materials. In one aspect, the composite stamp comprises a deformable layer and a rigid support layer, and the deformable layer and the support layer have different chemical composition and mechanical properties. The deformable layer optionally comprises a composite polymer layer, such as a reinforcing layer having a combination of fibers and one or more polymers such as, for example, glass or elastic fibers, for example, microparticles or microparticles or combinations thereof .

The deformable layer may be an elastomer layer. "Elastomer" or "elastomeric" relates to a material of a polymer which can be stretched or deformed and returned to its original form, rather than a substantially constant deformation. In general, elastomers undergo substantially elastic deformation. Exemplary elastomers useful in the present invention may include polymers, copolymers, composite materials or composites of polymers and copolymers. The elastic layer is associated with a layer comprising at least one elastomer. The elastic layer may also include dopants and other non-elastic materials. Elastomers useful in the present invention include, but are not limited to, poly (dimethyl siloxane) (e.g. PDMS and h-PDMS), poly (methyl siloxane), partially alkylated Poly (methyl siloxane), poly (alkyl methyl siloxane), and poly (phenyl methyl siloxane), silicone modified elastomer, thermoplastic elastomer, styrenic material styrenic materials, olefinic materials, polyolefins, polyurethane thermoplastic elastomers, polyamides, synthetic rubbers, polyisobutylene, poly (styrene-butadiene-styrene- butadiene-styrene), polyurethane, polychloroprene, and silicon containing polysiloxane.

"Supported" refers to a micro or nanostructure that forms, for example, a semiconductor, on the surface (e.g., a transfer surface) of the stamp so that the device can be transferred to another surface Lt; RTI ID = 0.0 &gt; semiconductor device. &Lt; / RTI &gt;"Inking" relates to the step of picking up or transferring a micro or nano structure from a donor substrate to a stamp.

As used herein, the expressions "semiconductor device" and "semiconductor structure" are used interchangeably and relate generally to a combination of materials, structures, devices, and / or devices. Semiconductor devices can be fabricated from high quality single crystalline and polycrystalline semiconductors, semiconductor materials made through high temperature processing, doped semiconductor materials, organic and inorganic semiconductor and semiconductor materials and one or more additional semiconductor components and / Non-semiconductive components, such as insulating layers or materials, and / or composites of structures such as conductive layers or materials. Semiconductor devices include semiconductor devices and device components including, but not limited to, transistors, photovoltaics including photovoltaic cells, diodes, light emitting diodes, lasers, pn junctions, photodiodes, integrated circuits and sensors . In addition, semiconductor devices relate to portions or portions that form an end functional semiconductor.

"Semiconductor" refers to any material whose material has an electrical conductivity at a temperature of about 300 Kelvin or an insulator at a very low temperature. In the description of the invention, the use of the term semiconductor is interpreted to be consistent with conventional usage of microelectronics and electronic devices. Semiconductors useful in the present invention include, for example, device semiconductors such as silicon, germanium and diamond and Group IV compound semiconductors such as SiC and SiGe, AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP, InSb, InAs, InN and ⅲ-ⅴ as InP group semiconductor, Al _x Ga _{1 - x} as ⅲ-ⅴ Group source semiconductor alloy (group ⅲ-ⅴ ternary semiconductors alloys ) 3 , such as, II-VI semiconductors such as CsSe, CdS, CdTe, ZnO, ZnSe, ZnS and ZnTe, I-VII semiconductors such as CuCl, IV-VI semiconductors such as PbS, PbTe and SnS, PbI ₂ , MoS ₂ and GaSe semiconductor layer, an oxide such as CuO and Cu ₂ O and the like include a compound semiconductor such as a semiconductor. The term semiconductor includes intrinsic and doped semiconductors doped with one or more selected materials, including semiconductors having p-type doping materials and n-type doping materials, to provide useful electronic properties for a given application or device . The term semiconductor includes a composite material comprising a semiconductor and / or a mixture of dopants. Specific semiconductor materials useful in some applications of the present invention include but are not limited to Si, Ge, SiC, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InP, InAs, GaSb, InP, InAs, InSb, ZnO, ZnSe, ZnTe, CdS, CdSe, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, PbS, PbSe, PbTe, AlGaAs, AlInAs, AlInP, GaAsP, GnInAs, GaInP, AlGaAsSb, AlGaInP and GaInAsP. Porous silicon semiconductor materials are useful in applications of the present invention in the field of sensors and luminescent materials such as light emitting diodes (LEDs) and solid state lasers. Impurities of the semiconductor material are atoms, elements, ions and / or molecules other than the semiconductor material itself or any dopant provided in the semiconductor material. Impurities are undesirable materials present in semiconductor materials that can negatively affect the electronic properties of semiconductor materials, including, but not limited to, metals including oxygen, carbon, and heavy metals. Heavy metal impurities include, but are not limited to, elemental groups between copper and lead on the periodic table, calcium, sodium and all ions and their composites and / or complexes.

"Relief feature" refers to a feature that promotes dry-transfer printing of a semiconductor device from a donor substrate to a target substrate, such as a three-dimensional relief pattern, that protrudes, extends, It is related to protrusion. In one aspect, the relief feature of the deformable layer defines the printable area. "Printable surface area" or "area" relates to a portion of the stamp used in the transfer structure from the donor substrate to the target substrate. "Active surface region" is used interchangeably with "printable surface area &quot;. A "pattern of reel ripple features " is associated with a plurality of features including a plurality of nanostructures or microstructures, such as, for example, an array of features. A relief feature is a population that is required to satisfy a particular function, and can be configured in turn from a plurality of distinct groups. For example, one population may include a printing post that promotes lift-off and transfer of semiconductor devices. The other population may include a stability feature to secure a stamp without bending, twisting, or otherwise subject to unwanted deformation during lamination and / or exfoliation with the receiving substrate surface. In one aspect, each group is constructed from materials that have other geometries, dimensions, such as height, length, or width, or that cause other physical parameters, such as, for example, an effective Young's modulus for the group . In one aspect, the group comprises a plurality of sub-groups.

"Lamination" refers to a process of bonding a layer of a composite material or a process of bonding a layer of a first material or layer and a second layer or material (e.g., rigid backing and strengthening layers, Such as between a layer and a deformable layer, between a semiconductor element and a transfer surface or a receiving surface. "Delamination" relates to stamp transfer surface-semiconductor element separation or stamp transfer surface-receiving substrate separation. In particular, in embodiments where the stamp has a relief feature that is a printing post inked with a semiconductor element, the peel rate is related to the separation of the printing post surface from the semiconductor element. The exfoliation rate may be related to a single post face peeling off the individual semiconductor elements. Alternatively, the peel rate may be related to the spatially-averaged rate for all post-seeds within the printable surface area. In general, the treatments provided herein facilitate a high transfer gain and placement accuracy for a sufficiently high removal rate than conventional techniques. For example, the peel ratio can be two times higher, or up to 10 times higher, compared to the prior art without shear and without any measurable effect on transfer gain or placement accuracy.

"Substantially constant" relates to a variable that varies by less than 10% compared to the mean. For example, a sufficiently constant removal rate is associated with a rate that varies from an average rate to less than 10% over the separation cycle. A sufficiently parallel is related to a direction that is within at least 10% of the actual parallelism.

"Substrate" relates to structures or materials in which processing is guided, such as, for example, patterning, assembling and / or integrating semiconductor devices. The substrate may be, but is not limited to: (i) a structure in which semiconductor devices are assembled, deposited, transferred or supported; (Ii) an extended substrate, for example, an electronic device substrate; (Iii) a donor substrate having elements, such as semiconductor elements, for subsequent transfer, assembly or integration; And (iv) a target substrate that receives a printable structure, such as a semiconductor device.

"Placement accuracy" relates to the ability of a device to generate a pattern in a pattern transfer method or a selected area of a substrate. A "good placement" precision can produce patterning in a selected area of the substrate with spatial variations from a strictly accurate orientation of 5 microns or less, and in particular, to a method and apparatus capable of producing a pattern of semiconductor elements on a target substrate .

"Operably connected" relates to the organization of the layers and / or device elements of the composite patterning device of the present invention so that the functionality of the component or layer is maintained when connected. A layer or device element operably connected is associated with a layout, wherein the force applied to the layer or device element is communicated to another layer or device element. The operatively connected layer or device element may be in contact, such as a layer having internal and / or external surfaces in physical contact. Alternatively, the operatively connected layers and / or device elements may be located between two layers or between the inner and / or outer surfaces of the device elements, or between two or more layers or elements, May be connected to one or more connection layers, such as an enhancement layer. In one embodiment, the ridge layer and the enhancement layer are "operably connected" in order to withstand the higher activation forces that do not bend or have no ridge layer break in the enhancement layer, It suffers.

The invention may be better understood by the following non-limiting examples. All references cited herein are hereby incorporated by reference to the extent that they are inconsistent with the description herein. Although the description herein contains many limitations, they are merely illustrative of some presently preferred embodiments of the invention and are not to be construed as limiting the scope of the invention. Thus, for example, the scope of the invention will be determined by the appended claims and their equivalents, rather than by the examples given.

The processes provided herein achieve a high transfer gain of the printable semiconductor device with increased accuracy. The method described herein releases the printable semiconductor element from the side of the transfer printing stamp to the surface of the target substrate and overcomes the proposed change by the significant adhesion of the substrate used in conventional transfer printing. The adhesion of the substrate surface slows the peeling, adversely affects the transfer quality, and reduces the overall transfer gain. The proposed method and apparatus enable transcription printing of printable semiconductor elements on substrates with low adhesion surfaces and enable high speed printing of semiconductor elements that can be printed with controlled and optimized transfer stamp peel rates . The methods, systems and processes can be mounted on various sizes of elastic stamps and donors of different sizes, receiving or target substrates. A variety of multi-facet series and controlled tests are described in the following specification, exemplary embodiments and drawings, which illustrate the benefits and practice advantages of the described apparatus and transfer printing method.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the steps used in one embodiment of the invention to control the peeling of a transfer printing stamp. First, the stamp 10 has an array of printable semiconductor elements 20 using standard procedures as described in published dry transfer printing literature (see, for example, Khang et al., U.S. Patent Application 11 / 145,574) . In one aspect, the semiconductor element 20 is on the printing surface 72 that corresponds to the outer surface of the three-dimensional pattern of relief features 74. The stamp becomes close to the receiving substrate surface 30 (Fig. 1A) (for example, <100 mu m). After the correct optical arrangement of the stamp 10 on the receiving substrate 30 the stamp is in conformal contact with the substrate by the application of a uniform air force 35 on the stamping backing surface 40, (Fig. 1B). Then an in-plane shear force 50 (e.g. applied in a direction substantially parallel to the xy plane) results in an accurate displacement offset 65 (leaving the arranged position) 65, Or by precise displacement of the receiving and / or receiving substrate by moving the instrument head device (which fixes the stamp) by means of the stamping device (Fig. 1C). In this aspect, as long as the result is only the in-plane displacement or shear offset 65 between the stamp and the receiving substrate, without breaking the isometric contact between the inked stamp and the receiving substrate too quickly, as shown in Fig. 1C, Or displacement 50 may be applied to the stamp, the receiving substrate, or both. This shear force is transmitted to the bottom surface of the stamp printing post 70, which causes some elastic mechanical deformation of the stamp printing post 70. Finally, the stamp separates from the receiving substrate by moving the stamp 10 in the direction Z (80) in the perpendicular (Z) direction relative to the receiving substrate 30 and at the same time reducing the air force 35 applied to the stamp backing (FIG. The vertical movement is indicated by the arrow 80 in the vertical direction, where the vertical movement can be controlled by moving both with respect to the stamp 10, the substrate 30, or with respect to each other. The reduction in aerodynamic force is depicted by a decrease in the size of the arrow 35.

2A shows a three-dimensional schematic view of a composite stamp that facilitates uniform transfer of in-plane shear forces applied over the entire surface of the stamp (by a rigid stamp backing layer). The composite stamp consists of a ridge backing layer 201 connected to an upper surface 205 of an elastomeric layer 202 having relief 70 and recess 104 features. The stamping printing post pitch in the glass backing layer thickness 230, the elastomer layer thickness 231, X 211 and Y direction 221, the stamp printing post width and length 210 and 220, Other stamp sizes such as post height 212 can each independently influence the applied shear force and are optionally optimized to provide high gain and accurate transfer printing by the shear-offset method described herein. In one aspect, any one or more of these parameters are selected to achieve the desired transfer gain, placement accuracy, and / or delamination rate constancy. The Young's modulus of the elastomeric layer 202 and the shape of the stamp post 70 (Figure 2b) are arbitrarily adjusted to optimize the efficiency of the shear assisted stamp release method. In one aspect, any one or more of these parameters are selected to achieve the desired transfer gain and / or placement accuracy. For example, FIG. 2B shows an example of four different post shapes: standard (selectable height 212, width 210, length (not shown)), suction cup and reentrant profile re -entrant profiles.

3 illustrates an exemplary layout for stamp post alignment that includes printing posts 70 and stabilization features 320, such as an anti-sag feature 310. The anti- The printing posts 70 are considered for supporting printable semiconductor elements during a transfer printing cycle. The anti-sag feature 310 is considered to support the recessed area of the stamp 104 to avoid contact between these recessed areas and the surface of the donor / receiver substrate. Thus, in one embodiment, the anti-sag feature has a height that is less than the height 212 of the printing post shown in FIG. 2B. The locking feature 320 may be used to secure the stamp surface, the printing post 70, or the anti-sag feature 310, for example, when any feature has a high aspect ratio (e.g., height / width> It is possible to prevent buckling.

A schematic diagram of an apparatus capable of providing shear offset printing of semiconductor devices is provided in Fig. A composite stamp, such as any of the composite stamps described in 12 / 177,963 filed on August 29, 2008, is connected to the printhead head 500. Further details of the instrument head 500 are provided in, for example, compound stamps, apparatus for securing composite stamps, and 12 / 177,963, which is expressly incorporated herein by reference for the printing process. Reinforced composite stamp 400 as described in U.S. Patent Application Publication No. 12 / 177,963 describes a relief pattern (not shown) oriented along a reinforcement layer 410 between an elastomeric layer and / or an elastomeric layer and a ridge backing layer, And a rigid backplane layer 201 connected to an elastomeric layer 202 having a plurality of elastomeric backing layers 74. Actuator 420 is any device known in the art that is capable of providing controlled displacement, such as in-plane displacement. A pressure controller 430, such as an air force controller, applies controllable force to the stamp top surface 40 by application of a user-selectable uniform pressure 35 across the stamp top surface 40 to provide. 4A, the shear offset is provided by the in-plane displacement of the stamp due to the in-plane displacement of the instrument head 500 to which the composite stamp 400 is connected. As shown in FIG. 4B, alternatively, the shear offset is provided by the in-plane displacement of the receiving substrate 30 with respect to the composite stamp 400. As used herein, "in-plane displacement" is related to displacement in the xy plane, as indicated by the xyz axis in Fig. If the direction of displacement is within 10%, within 5%, or within 1% in parallel with the plane defined by the xy-axis shown in FIG. 4, the displacement is referred to as " in plane &quot;.

Figure 5 provides the transfer gain of chiplets from the enhanced composite printing stamp (represented schematically in Figure 4a) to the receiving substrate. The reinforced composite stamp is mounted on a dry transfer printing mechanism (shown in Figure 4C). The receiving glass substrate is coated with a thin layer of BCB (Cyclotene, Dow Chemical Co.). Each data point in Figure 5 represents the average transfer gain of four consecutive dry transfer prints of an alignment of 256 silicon chips corresponding to a sum of 1,024 chips per data point on the graph. For all tests, the silicon chip has the following physical dimensions: length = 167 m, width = 50 m, thickness = 5 m. The insert of Figure 5 is an optical image of six transferred silicon chips. These silicon chips have an alignment of 13 metal interconnect pads on their top surface. The stamp has a 16 x 16 post alignment with the following physical dimensions: post pitch = 185 x 185 m, post length = 167 m, width = 50 m, thickness = 40 m. The stamp has the following physical dimensions: disk diameter = 76.2 mm, thickness: ~ 200 μm, glass backing layer. The reinforcing layer of the stamp is a 4-Harness Satin style weave pattern, a style 120E-glass fiber glass structure with a weight density of ~ 3Oz / Yd2 and an average thickness of 90-115 [ 120E-Galss fiberglass fabrics). &Lt; / RTI &gt; The reinforcement ring is laser cut in the form of a perforated ring with the following physical parameters: an inner diameter of 54 mm, an outer diameter of 120 mm, and a hole diameter of 2 mm. Constant shear offsets are applied to reinforced composite stamping flanges throughout the entire stamping step. Other shear offset values are used for each test to obtain an average transfer printing gain that varies with the offset, as summarized in FIG. The zero shear offset corresponds to a conventional transfer printing process that does not use any shear offsets. These results indicate that the shear force transferred to the stamp transfer printing post provides a significant increase in the transfer printing gain including the chitlet transfer printing gain. Figure 5 shows that under these experimental conditions, providing a shear offset of 50 mu m represents a gut that increases the semiconductor transfer gain by 95% to 99.5% or more.

In order to better understand the physical mechanism supporting this process, a finite element simulation is performed. Figure 6a shows a schematic view of a model used to study peeling of a single printing post. The shear offset 50 and the uniform force 801 are applied to the elastomeric layer 202 having the printing posts 70 with an evolving contact interface 500 between the printing force of the stamp and the receiving substrate 30. [ Is applied to the ridge stamp layer (201) which is in contact with the ridge stripe layer (201). A non-linear force boundary condition is used to facilitate the convergence of Newton-type iterative algorithms used by the simulation software, a low-order boundary condition:

This boundary condition does not accurately design Van der Walls and short range repulsion forces present at the stamp-substrate interface, but nevertheless suffices to adequately predict the shape of the peel-off printing post. 6B shows a schematic view of a printing post (50 um wide, 40 um tall) for peeling off the substrate against a 10 um shear offset applied to a stamp glass backing layer (200 um thick) as part of interface 500 with stripped length 610 And a screen shot copy of the obtained simulation run.

Analysis of the simulation results shows that the shear offset peeling process described herein is effective with respect to two other aspects. First, the shear offset is an effective process for controlling the peel rate, especially the peel rate of the stamp printing post from the target or receiving substrate. Figure 7b shows the change in the stamp printing post peel ratio ratio as a function of the shear offset applied to the stamped glass backing layer. The "peel ratio ratio" relates to the horizontal displacement of the post-peel separation preceding the vertical displacement of the stamp glass backing layer. These in silico results indicate that the application of the shear offset to the stamped glass backing results in a substantial reduction of the stamp printing post peel ratio and a corresponding decrease in energy required to peel the stamp (see FIG. 7A). A slower and stable stamp peel ratio generally results in higher printing gain on most sides. However, the application of shear offsets takes into account the higher exfoliation ratios performed, without loss of printing gain, as compared to conventional techniques that do not apply shear offsets.

Even if the stamp is peeled off at a low peel rate, it is difficult to obtain a high transfer printing gain on those surfaces which generally oppose the plastic substrate, especially those surfaces which are not ultra-smooth. The "shear" method described herein significantly improves the printing gain and the energy required to separate the printing posts from the target substrate can be minimized (see FIG. 7A). An important part of this energy is stored as mechanical strain energy in the modified stamp printing post. Figure 7a shows a generalized change in energy for stripping a stamp printing post as an action of a shear offset applied to the stamped glass backing. This energy is obtained by incorporating the work done by the boundary force at the interface between the stamp printing post and the chiplet. These in silico results suggest that minimization of adhesion work is responsible for the empirically observed enhancement of the transfer printing gain.

In order to obtain a high transfer printing gain, it is required to maintain a constant release rate of the transfer printing stamp. When the composite stamp is peeled from the target substrate, the finite element simulation is performed to analyze the change in the stamp peel ratio. 8A is a schematic view of a stamping system used to study peeling for a flat transfer surface joining structure. The same non-linear force boundary condition is used to design the unfolded contact interface 500 between the stamp transfer surface on the outer surface of the elastomeric layer 202 connected to the ridge backing layer 201 and the target substrate receiving surface 30 . The outer edge 803 of the stamped glass backing layer 201 is subjected to a forced position boundary condition (? X = 0,? Z). Uniform force (e.g., force per unit area 801) is applied to the composite stamped glass backing (applied force 801), which simulates the action of the air force applied to the upper surface of the stamp (e.g., the upper surface of the ridge backing layer) Lt; / RTI &gt; (corresponding to the top surface 40). This study is conducted on a composite stamp (e.g., a flat transfer surface) that has no relief features to obtain a continuous change before stamp removal. This particular situation also simplifies the analysis and reduces the complexity of the computer model mesh. 8B shows a coded plot of the composite stamp of FIG. 8A that is peeled (610) from the substrate receiving surface 30. FIG. The stamp deformation is magnified by a factor 100 to emphasize the shape of the stamped area 610 that has been peeled from the substrate 30. The designed composite stamp has a width of 100 mm, a glass backing thickness of 200 um, and an elastomer layer thickness of 200 um. In this particular case, the stamp edge 803 is forced to move vertically 100 占 퐉 from the target substrate 30. A uniform pressure of 0.5 kPa is applied to the composite stamped glass backing top surface 40.

Two different parametric simulations are performed to separate the vertical movement of the stamping glass backing edge to the influence of the air force and the stripping of the stamp. First, the stamp glass backing outer edge 803 is maintained at the Z-offset position (100 占 퐉 vertical separation from the target substrate 30), and the air force applied to the glass backing is progressively reduced from 5 kPa to 0.5 kPa.

FIG. 9A shows the change in stamp lamination edge length 801 (see FIG. 8B) as an effect of applied air pressure. The "stacked edge length" is related to the length of the stamp in conformal contact with the target or receiving substrate 30. During the process of shear offset printing, the stacked edge length decreases from maximum to zero at the beginning of the transfer when the stamp is vertically removed from the receiving substrate. These results show that the stamp laminate edge length decreases rapidly when the applied air pressure drops below 1 kPa. It is therefore desirable to maintain some level of residual air pressure in the composite stamp during the stripping step to avoid a sudden change in stamping wetting from the stripping rate. 9A, the air pressure applied to the glass backing is maintained constant (0.5 kPa) and the stamp glass backing outer edge 803 is gradually moved away from the target substrate in the vertical direction.

9B shows a change in the stamp laminate length 801 as an action of the stamp glass backing outer edge vertical displacement (relating to the receiving substrate surface). These results indicate that the stamp laminate edge length is rapidly falling off the substrate during the initial movement of the glass backing outer edge. It is therefore desirable to maintain a higher air force on the composite stamp during the initial stripping step to avoid a sudden change in stamping from the stripping rate. This suggests that it may be beneficial to apply the time-varying pressure to the top surface of the stamp, especially the top surface of the ridgebacking layer, which decreases at the initial maximum value.

In short, these silico effects can be achieved by controlling the air pressure applied to the composite stamp backing at the beginning of the stripping cycle to maintain better and more precise control over the composite stamp stripping rate, and to control the air pressure applied to the stamp glass backing outer edge at the end of the stripping cycle It is suggested that it is desirable to control movement. If the applied air pressure and outer edge vertical movement are precisely adjusted, a fixed and constant stamp peel ratio can be obtained, thereby achieving a substantially constant peel ratio with an improvement in transfer printing gain.

10A and 10B are typical protocols for adjusting or optimizing air pressure and vertical displacement during a stamp peeling cycle wherein the air pressure (Figure 10A) and the stamp edge vertical separation (Figure 10B) are time (t = 0, T = 1 end of the peel cycle). During the first portion of the stripping cycle, the air pressure applied to the stamped glass backing is drastically reduced and the stamped outer edge is held at the fixed Z position. During the second portion of the stripping cycle, the air pressure applied to the stamped glass backing is kept constant at a relatively low value and the stamped outer edge is moved vertically away from the target substrate in accordance with a logarithm equation. Fig. 10C shows a change with time of the stamp lamination length. A linear plot shows that the peel ratio is virtually constant. These results indicate that a stable stamp peel ratio can be obtained by selectively varying the parameters, e.g., the pressure and vertical separation distance over the top surface of the stamp over time.

Any reference throughout this application, for example a patent document that is issued or registered, or an equivalent; Patent application publications; And non-patented papers or other source data are incorporated herein by reference in their entirety and hereby incorporated by reference in their entirety as if each were incorporated herein by reference and the scope of each reference is at least partially (For example, a partially contradictory reference is included as a reference except for the partially contradictory portion of the reference).

It is to be understood that the terms and expressions used herein are used as terms of description and not of limitation, and are not intended to be used as terms of any of these terms and expressions except for the equivalents of the features shown and described or portions thereof, Lt; / RTI &gt; Thus, although the present invention has been specifically described by preferred embodiments, it will be appreciated by those skilled in the art that the preferred embodiments and optional features, modifications and variations of the concepts described herein may be resorted to by those skilled in the art, But may be understood as being considered within the scope of the invention as defined by the claims. The detailed embodiments provided herein are illustrative of advantageous embodiments of the invention and will be apparent to those skilled in the art that the present invention may be practiced using many variations of the apparatus, device elements and method steps set forth herein before. As will be apparent to those skilled in the art, methodologies useful for the present method may include any number of combinations and processing elements and steps.

When a substitutable group is described herein, it will be understood that all individual members of that group and subgroup are described separately. When Markush groups and other groupings are used herein, all individual members of the group and all possible configurations and sub-configurations of groups are included in the specification.

Any form or combination of elements described or illustrated herein can be used to carry out the invention, unless stated otherwise.

Every time a range is given in the specification, for example, a temperature range, a size or distance range, a time range, or all individual values contained in a composition or concentration range, a given range, as well as all intermediate ranges and subranges are included in the specification . Any sub-ranges or ranges or ranges of sub-ranges included in the specification herein may be excluded from the scope of the claims herein.

All patents and publications mentioned in the specification are indicative of the level of skill in the art to which the invention pertains. The references cited herein are hereby incorporated by reference in their entirety to indicate the state of the art as their publication or submission date, and this information, if necessary, may be incorporated herein without the specific examples of the prior art do. For example, if a component of a content is claimed, the composition of the contents herein is known and available to the applicant's invention, including the composition provided in the reference cited herein &Lt; / RTI &gt;

As used herein, "comprising" is synonymous with "including,""containing," or "characterized by," and includes, , Do not exclude recited elements or method steps. As used herein, "consisting of" excludes any element, step, or ingredient that is not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel features of the claims. In each case, any of the terms " comprising, "" consisting essentially of" and "constituting" The invention described herein as it may be suitably practiced in the absence of any elements or elements, limitations or limitations not specifically described herein.

All of the known functional equivalents of these materials and methods are included in this invention. The terms and expressions which have been used are used as terms of description and not of limitation, and are not intended to be used as terms or expressions of such equivalents of the features shown or described or parts thereof, but various modifications may be made within the scope of the claimed invention . Accordingly, although the present invention has been specifically described by preferred embodiments and optional features, it will be understood by those skilled in the art that the selection features, modifications, and variations of the concepts described herein may be resorted to, But may be understood as being considered within the scope of the invention as defined by the claims.

Claims (33)

A method of printing a transferable semiconductor device,
a) providing an elastomeric staple having a transfer surface including a three-dimensional pattern of a relief feature supported by the semiconductor element and at least partially contacting the semiconductor element; ;
b) providing a substrate having a receiving surface;
c) establish conformal contact between the semiconductor element and the receiving surface supported by the transfer surface of the elastomeric stamp, thereby establishing contact of at least a portion of the semiconductor element with the receiving surface;
d) offsetting said elastomeric stamp by a horizontal distance relative to said receiving surface, thereby removing at least part of said relief feature pattern from said transfer surface or said receiving surface without mechanical deformation ); And
e) separating the stamp from the receiving surface, thereby printing the semiconductor element on the receiving surface,
Wherein the offsetting step comprises:
Wherein the upper portion of the relief feature is moved relative to the substrate without moving the transfer surface of the elastomeric stamp supporting the semiconductor element relative to the substrate, Wherein the transfer surface is separated from the transfer surface.
The method according to claim 1,
Wherein the conformal contacting step is established by applying air pressure to the top surface of the elastomeric stamp. &Lt; Desc / Clms Page number 19 &gt;
The method according to claim 1,
Wherein the step of offsetting comprises applying an in plane displacement to the elastomeric stamp. &Lt; Desc / Clms Page number 20 &gt;
The method of claim 3,
Wherein the in-plane displacement comprises a horizontal displacement of the top surface of the elastomeric stamp with respect to the receiving surface of between 5 microns and 100 microns. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
3. The method of claim 2,
Wherein said separating step comprises reducing said air force applied to said upper surface of said stamp. &Lt; Desc / Clms Page number 13 &gt;
The method of claim 1, wherein the elastomeric stamp comprises:
a) an elastomeric layer having an upper surface facing the transfer surface; And
b) a rigid backing layer having a bottom surface,
Wherein said bottom surface is positioned adjacent to an upper surface of said elastomeric layer. &Lt; RTI ID = 0.0 &gt; 18. &lt; / RTI &gt;
The method according to claim 6,
The elastomeric stamp further comprises a reinforcement layer operably connected to the ridge backing layer,
Wherein the enhancement layer has an opening that is perpendicular to at least a portion of the relief feature on the transfer surface.
The method according to claim 1,
Further comprising the step of mounting the elastomeric stamp on a dry transfer printing tool,
Wherein said offset step applies an in-plane displacement to said dry transfer printing means, thereby causing a mechanical deformation of at least a portion of said relief feature.
9. The method of claim 8,
Further comprising applying pressure to an upper surface of the mounted stamp to thereby establish a projective contact between the stamp and the receiving surface.
10. The method of claim 9,
Wherein the stamp is separated from the receiving surface by moving the transfer printing means mounted on the elastomeric stamp in a direction perpendicular to the receiving surface.

11. The method of claim 10,
Wherein said pressure changes during said vertical movement separating said stamp from said receiving surface. &Lt; Desc / Clms Page number 19 &gt;
12. The method of claim 11,
Wherein the pressure is reduced from a maximum value to a minimum value, wherein the maximum value is between 4 kPa and 10 kPa, and the minimum value is between 0 kPa and 2 kPa.
13. The method of claim 12,
Wherein the pressure reduces the rate and the vertical motion rate is selected to provide a delamination rate of the relief feature from the receiving surface, and the delamination rate of the relief feature is selected in a peeling cycle Wherein the ratio is a ratio that varies from an average ratio to 10% or less.
The method according to claim 1,
Wherein the relief feature further comprises a plurality of posts. &Lt; RTI ID = 0.0 &gt;&lt; / RTI &gt;
15. The method of claim 14,
Wherein said plurality of posts have a contacting area fraction on said transfer surface selected from the range of 1% to 25%. &Lt; Desc / Clms Page number 17 &gt;
16. The method of claim 15,
And a plurality of scattered feature stabilization features between the posts,
Wherein the stationary feature has a contact area smaller than the contact area of the post. &Lt; Desc / Clms Page number 13 &gt;
The method according to claim 1,
The semiconductor printing provides a transfer printing output,
The above-
a) more than 99.5% of the receiving surface coated with a thin layer of adhesive,
and b) 99.5% or more of a stamp peel ratio of 1 mm / s or more.
The method according to claim 1,
a) optically aligning the stamp and the receiving surface;
b) positioning the semiconductor device within a vertical separation distance of no more than 100 占 퐉 from the receiving surface; And
c) applying pressure to the upper surface of the stamp, thereby establishing a projective contact between the stamp and the receiving surface. &lt; Desc / Clms Page number 13 &gt;
19. The method of claim 18,
Wherein the pressure is applied by use of a constant air force to the upper surface of the stamp.
The method according to claim 1,
Wherein said pattern of relief features supports a plurality of semiconductor elements. &Lt; Desc / Clms Page number 20 &gt;
The method according to claim 1,
Wherein the receiving surface is applied to only a portion of the adhesive. &Lt; RTI ID = 0.0 &gt; 18. &lt; / RTI &gt;
The method according to claim 1,
Wherein said separating step comprises removing said stamp on said receiving surface by applying a vertical offset to said stamp or said receiving surface. &Lt; Desc / Clms Page number 20 &gt;
2. The method of claim 1,
a) applying an in-plane displacement to the stamp,
b) applying the in-plane displacement to the receiving surface.
The method according to claim 1,
a) applying an aerodynamic force to at least partially establish said conformal contact; And
b) vertically separating the stamp from the receiving surface,
Wherein the air force varies over a first time interval and the vertical separation remains constant over the first time interval and the air force is held constant over a second time interval that does not overlap the first time interval, Wherein vertical separation is increased during the second time interval to maintain a peeling rate that deflects less than 5% at an average separation rate over the first and second time intervals.
The method according to claim 1,
Wherein the transfer efficiency of the semiconductor element is improved as compared to the transfer yield of the method in which the elastomeric stamp is not offset.
26. The method of claim 25,
Wherein the improvement in the transfer yield relative to the non-offset transfer yield is greater than 4%.
The method according to claim 1,
Wherein the mechanical deformation in the elastomeric stamp relief feature reduces the initial delamination energy for transfer of the semiconductor device from the transfer surface of the elastomeric stamp.
28. The method of claim 27,
Wherein the decrease in the initial peel energy is 0.1 to 0.8 times the peel energy of the non-offset elastomer stamp.

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